The SQL Self JOIN syntax

The general syntax is:

1. SELECT column–names
2. FROM table–name T1 JOIN table–name T2
3. WHERE condition

T1 and T2 are different table aliases for the same table

SQL Self JOIN Examples

Problem: Match customers that are from the same city and country

1. SELECT B.FirstName AS FirstName1, B.LastName AS LastName1,
2. A.FirstName AS FirstName2, A.LastName AS LastName2,
3. B.City, B.Country
4. FROM Customer A, Customer B
5. WHERE A.Id <> B.Id
6. AND A.City = B.City
7. AND A.Country = B.Country
8. ORDER BY A.Country

A and B are aliases for the same Customer table.
Results: 88 records